Rao, Ch. Srinivasa; Chandrasekharam, M.; Patro, Balaram; Ila, Hiriyakkanavar; Junjappa, Hiriyakkanavar Tetrahedron, 1994, vol. 50, # 19 p. 5783 - 5794 doi: 10.1016/S0040-4020(01)85646-5